A graded aggregate layer is commonly used above the compacted subgrade.
Its functions include:
- Distributing loads
- Improving structural stability
- Supporting drainage
- Reducing differential settlement
- Providing a stable platform for the upper base
Typical aggregate thicknesses may fall within approximately 150–200 mm, but actual thickness should be calculated according to:
- Soil bearing capacity
- Climate
- Frost conditions
- Drainage
- Expected loading
- Sports application
- Local engineering requirements
The aggregate should be placed in controlled lifts and compacted appropriately rather than simply dumped and rolled once.
5. Concrete vs. Asphalt Base
Two common hard-base solutions are concrete and asphalt.
| Feature | Concrete Base | Asphalt Base |
|---|---|---|
| Structural stability | High when properly designed | High when properly designed |
| Surface preparation | Requires careful finishing | Requires careful paving and compaction |
| Construction | Relatively familiar and widely available | Efficient for large areas |
| Joints | Expansion/control joints require consideration | Fewer conventional concrete joints |
| Temperature behavior | Can crack if poorly designed | Can soften or deform under certain conditions |
| Cold-climate considerations | Joint and frost design are important | Frost and sub-base design are important |
| Turf compatibility | Must meet moisture/flatness requirements | Must meet temperature/flatness requirements |
Neither system is universally “better.”
For a particular project, the appropriate solution depends on the site, climate, drainage, structural design, turf system, and construction budget.
Leave a Reply